1. Field of the Invention
The present invention is directed to a system that automatically aligns two or more sensors using the cross correlation of the images sensed by the sensors and thereafter electronically corrects for spatially varying misregistration errors and, more particularly, to a system that achieves subpixel alignment by using a rotational mathematical cross correlation with interpolation or peak hunting to find the position of highest correlation, thereby determining the misregistration, and to move the sensors into place based on the position of highest correlation and then correct for regionally located, spatially varying misregistration errors caused by chromatic aberrations in a lens system providing the image to the sensors.
2. Description of the Related Art
In multiband or multicolor imaging systems in which two or more image sensors are placed behind an optical beam splitter, the sensors must be aligned relative to each other in the imaging plane so that they sample the image in the correct or same location. Usually one sensor, called the reference sensor, is fixed in the image plane and the others are aligned to it. Two approaches are typically taken to align such multi-sensor imaging systems. In the first optical approach, an operator uses special magnifying optics to look into the entrance face of the beam splitter and align reference registration marks, bonding pads or other suitable features on the sensors to those on the reference. A second, active approach is to have the system operating and imaging a test scene which includes registration marks. While watching a monitor or other visual display, the sensor under alignment is adjusted by an operator until images are brought into proper registration or waveforms have the proper qualities. Both of these approaches can be automated to some degree.